Poor sister takes the test again (6)

I believe the answer is:

resits

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'the test again' is the definition.
I don't know anything about this answer so I cannot tell whether it can be defined by this definition.

'poor sister' is the wordplay.
'poor' is an anagram indicator.
'sister' with letters rearranged gives 'RESITS'.

'takes' is the link.

Can you help me to learn more?

(Other definitions for resits that I've seen before include "Exams taken for a second time" , "Takes the examination again" , "Does paper over" , "takes 15 [EXAM] again" .)

I've seen this clue in The Irish Times.

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